RFR: 8327492: Remove applet usage and update DisposeInActionEventTest.html [v11]

[Alisen Chung]

> Root cause of the test failure was fixed with https://bugs.openjdk.org/browse/JDK-8316931, updating this test since the other fix also included a test update.

Alisen Chung has updated the pull request incrementally with one additional commit since the last revision:

  null check for system tray before remove

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17838/files
  - new: https://git.openjdk.org/jdk/pull/17838/files/9e053cae..60bb2701

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17838&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17838&range=09-10

  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17838.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17838/head:pull/17838

PR: https://git.openjdk.org/jdk/pull/17838